A hydration system includes a liquid reservoir, a bottleneck plug, a tube, a hydration valve (e.g., bite valve), and a flow-restricting device (e.g., check valve). The tube comprises a first end for coupling to the liquid reservoir via the plug, a second end having the hydration valve, and the flow-restricting device interposed between the liquid reservoir and the hydration valve. The plug may be inserted into a variety of bottlenecks.